Project 3: Carbon Nanotube X-Ray for in-vivo Cancer Detection X-rays are indispensable in many medical applications including cancer detection, characterization and treatment. The basic design of the x-ray tube however has not changed significantly: a thermionic cathode is used to produce electrons which strike on a metal target to generate x-ray. It has several intrinsic drawbacks that have limited the effectiveness and advancements of the x-ray technologies. These include high cathode operating temperature (~1000[unreadable]C) which prevents miniaturization and novel source configurations that can increase imaging speed and accuracy, high imaging dose which causes radiation damage, and low temporal and spatial resolution which affects the size and accuracy of the features can be detected. Carbon nanotube (CNT) based field emission x-ray sources have the potential to not only overcome these limitations but also enable new novel imaging modalities. Preliminary results from our group have demonstrated that the CNT x-ray technology: (1) can generate programmable pulsed x-ray waveform with high temporal resolution which readily enables synchronized/gated imaging and temporal Fourier processing to increase signal/noise ratio; (2) allows novel source configurations such as scanning multi-beam x-ray sources for dynamic and high-speed tomographic imaging; (3) miniaturizes x-ray sources with the possibility of "x-ray on chip" technologies. Specific CNT x-ray technologies for cancer imaging and radiotherapy for humans and animal model research will be developed. It will be carried out in three phases including technology development, evaluation, and transition into clinical use. Phase 1 concentrates on the development of: (1) CNT field emission x-ray sources, in particular multi-beam field emission x-ray (MBFEX) sources that can generate spatial-temporal programmable scanning x-ray without mechanical motion; (2) temporal Fourier digital radiography (TFDR) method for low-dose and high-speed imaging; (3) stationary ultrafast micro-computed tomography (micro-CT) scanner for dynamic small animal imaging; (4) stationary tomosynthesis and CT systems for imaging of human breast cancer; and (5) a novel micro- RT (radiotherapy) system that can be combined with micro-CT for guided conformal radiotherapy for cancer research on small animal models. In Phase 2 these new technologies will be evaluated using phantoms and animal models and will be utilized to investigate lung and colon cancers in specific mouse models developed at UNC. In Phase 3, fully functional and user-friendly prototypes will be constructed for clinical and animal model research use